(25 days)
Coamatic® LR Antithrombin is intended for the quantitative determination of the heparin cofactor activity of antithrombin (AT) in human citrated plasma. All components of the kit are in liquid formulation (LR = Liquid Reagents).
Coamatic® LR Antithrombin is intended for the quantitative determination of the heparin cofactor activity of antithrombin (AT) in human citrated plasma. All components of the kit are in liquid formulation (LR = Liquid Reagents).
Antithrombin is the most important natural inhibitor of the coagulation cascade. By inhibiting the coagulation proteases, especially thrombin, factor Xa and factor IXa, antithrombin prevents uncontrolled coagulation and thrombosis. Plasma is incubated with an excess of Factor Xa (FXa) in the presence of heparin. The residual activity of FXa is determined by the rate of hydrolysis of the chromogenic substrate S-2772. The pNA release measured at 405 nm is inversely proportional to the AT level in the range 15-125% of normal plasma.
Here's a breakdown of the acceptance criteria and study details for the Coamatic® LR Antithrombin device, based on the provided text:
Acceptance Criteria and Device Performance
| Acceptance Criteria Category | Specific Metric (If available) | Acceptance Criteria | Reported Device Performance | Comments |
|---|---|---|---|---|
| Method Comparison | Slope | N/A | 1.011 | The correlation with the predicate device is excellent, indicating high agreement. |
| Intercept | N/A | 0.4889 | ||
| Correlation coefficient (r) | N/A | 0.995 | This value is very close to 1, demonstrating a strong linear relationship. | |
| Precision | Within-run CV% (114% AT) | N/A | 1.96% | Excellent precision at high AT levels. |
| Within-run CV% (59% AT) | N/A | 6.21% | Good precision at mid AT levels. | |
| Within-run CV% (29% AT) | N/A | 8.45% | Acceptable precision at low AT levels, though slightly higher than at other levels. | |
| Total CV% (114% AT) | N/A | 3.52% | Excellent overall precision at high AT levels. | |
| Total CV% (59% AT) | N/A | 6.43% | Good overall precision at mid AT levels. | |
| Total CV% (29% AT) | N/A | 11.09% | Acceptable overall precision at low AT levels. |
Note: The document does not explicitly state pre-defined numerical "acceptance criteria" for the slope, intercept, r-value, or CV%. Instead, it presents the results from which the FDA made a substantial equivalence determination based on the overall performance compared to the predicate device. The values presented here are the "reported device performance."
Study Details
2. Sample Size and Data Provenance
- Sample Size for Test Set: 61 citrated plasma samples.
- Data Provenance: Not specified in the provided text (e.g., country of origin, retrospective or prospective).
3. Number of Experts and Qualifications for Ground Truth
- Not Applicable (N/A): This type of information is usually relevant for medical imaging or AI diagnostic devices where human experts interpret data. For an in vitro diagnostic (IVD) assay like this, the "ground truth" is typically established by a reference method or validated analytical procedure rather than human expert consensus. The comparison is made against the predicate device.
4. Adjudication Method for Test Set
- Not Applicable (N/A): Adjudication methods (like 2+1, 3+1) are used to resolve discrepancies in human expert interpretations, which is not relevant for this type of IVD device study. The comparison is objective, based on analytical measurement.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC study was not done. This type of study is primarily for medical imaging devices where different human readers evaluate cases with and without AI assistance. This device is an automated IVD assay.
6. Standalone (Algorithm Only) Performance Study
- Yes, a standalone study was done. The "Method Comparison" section directly assesses the performance of the Coamatic® LR Antithrombin assay on the ACL Futura against the predicate device (IL Test™ Liquid AT) on the ACL 9000. This is a direct measurement of the device's performance as an algorithm/test system. The "Precision" study also assesses the standalone analytical performance of the device on the ACL Futura.
7. Type of Ground Truth Used
- Predicate Device/Reference Method: The "ground truth" or reference for comparison was the IL Test™ Liquid Antithrombin on the ACL 9000, which is the legally marketed predicate device. This implies that the predicate device is considered the established method for determining Antithrombin levels in this context.
8. Sample Size for Training Set
- Not Applicable (N/A): The document describes a traditional analytical validation for an IVD assay, not a machine learning or AI-driven device that requires a training set. The device itself is a reagent kit and instrument system.
9. How Ground Truth for Training Set Was Established
- Not Applicable (N/A): As there is no training set mentioned or implied for a machine learning algorithm, this question is not relevant.
§ 864.7060 Antithrombin III assay.
(a)
Identification. An antithrombin III assay is a device that is used to determine the plasma level of antithrombin III (a substance which acts with the anticoagulant heparin to prevent coagulation). This determination is used to monitor the administration of heparin in the treatment of thrombosis. The determination may also be used in the diagnosis of thrombophilia (a congenital deficiency of antithrombin III).(b)
Classification. Class II (performance standards).